Insecticide



junction with the usual Patented Feb. 2, 1932 snssz KARL MARX AND HANS W'E SC HE,

NEW 20m:

No brewing. Application filed July 5,

The invention relates to improvedsinsecticides and is based on the observation that the esters of oxalic acid and the derivatives and substitution products of these esters are very effective in destroying insects. It has" been stated that they even act against muscarians, for instance musca domestica, stolnaxys calcitrans. As known in the art, insects of thiskind' are veryresistant against the action of the synthetic insecticides. The said esters may be appiied in any desiredmanner, for instance by scattering in condiluents or vehicles or by spraying in form of a solution in an, organic solvent or in form of an aqueousemulsion' prepared in the known manner.

\The oxalic acid esters may be mixed with other insecticides. Natural roducts containing efiective insecticides, ibr example pyrethrum, may be extracted with the esters and the extract may be applied in the manner described above; Extracts of this mentioned natural product prepared with other solvents maybe mixed with oxalic acid esters. -By addition of a viscous oil, for instance paraf-v fine oil, to the" spraying preparations the fine- 1y sprayed substanceremainsfior a long time suspended in the air.

The esters are efiective in killing insedts, even when applied in very small quantities. When using oxalic acid diethyl ester, a quantity of 1-2 ccm. sprayed in 1 ohm. of the room is suflicient todestroy completely even many flies which are not killed bv other well known preparations, Similar etiects are ob-' tained by a preparation 'made by mixing an ester of oxalic acid with an extract of pyrethrum in any solvent.

To prepare an emulsion especially for combatting bugs and lice 5 parts of oxalic acid ethyl'ester are mixed with-5 parts of butyl alcohol and to the mixture are added parts of an emulsifying preparation, for 'instance a solution of.50 percent. strength of the sodium salt of"dibutylnaphthalenesulfonic acid. The mixture is then diluted with water to form 100 parts. An emulsion 9f 2 per cent. strength of this stock preparation yields an excellent spraying agent. I

It is obvious to all skilled in the art that on missile in ANHALT, WINTHROP CHEMICAL COMPANY, 1110;, on NEW YORK.

Y natures.

GERMANY, ASSIGN'ORS TO N. Y., A CORPORATION OF msncrrcmn 1928, Serial No.f290,98, and in Germany May 9, 1928.

our present invention is not limited to the details mentioned above. Instead ofoxalic acid diethyl ester there may be used other esters;

of the oxalic acid, for instance the dimethyl ester.

-What we claim is:

1. An insecticide containing as an active constituent an aliphatic ester of oxalic acid.

2. An insecticide containing as an active constituent oxalic acid diethy'l'ester.

3. An insecticide containing as an active constituent oxalic acid dimethyl ester.

In testimony whereof, we aflix our sig- KARL MARX. HANS WESOHE. 

